The vision-aided 3D display technology refers to a display technology capable of watching 3D effect with the aid of 3D glasses, 3D helmets or other vision-aided equipment. The vision-aided 3D display technology mainly includes: color separation 3D display technology, polarizing 3D display (Film Pattern Retarder, FPR for short) technology, shutter 3D display (Shutter Glass, SG for short) technology or helmet 3D display technology, etc. The color separation 3D display technology is a vision-aided 3D display technology, based on the spectral principle of colors, for allowing the left eye and the right eye to watch left and right parallax images of different spectrums so as to achieve 3D effect if an audience wears a pair of color separation glasses. The polarizing 3D display technology is a display technology, based on the polarization principle of light and the binocular parallax principle, for allowing the left eye and right eye of an audience who wears a pair of polarizing glasses to watch parallax images in different polarization directions so as to achieve 3D effect. The shutter 3D display technology allows an audience who wears a pair of synchronous timing shutter glasses to watch left and right parallax images sequentially and alternately displayed on a display screen so as to watch a 3D image. The helmet 3D display provides left and right parallax images to an audience by using two relatively independent display screens and allows the audience to be completely immersed in the displayed scene. If the left and right images displayed by the helmet are an image pair with horizontal parallax in a same scene, the audience may watch the 3D image of this scene.
At present, the mainstream vision-aided 3D display technology includes shutter 3D display technology and polarizing 3D display technology. The timing shutter glasses used by the polarizing 3D display technology are relatively expensive, but displayed pictures may keep fairly high resolution and quality. The polarizing glasses used by the polarizing 3D display technology is relatively cheaper, but the displayed picture is relatively rough as each eye only sees half of a picture. In view of the advantages and disadvantages of the shutter 3D display technology and the polarizing 3D display technology, RealD has proposed an RDZ technology in 2011. The RDZ display technology is a technology between the shutter 3D display technology and the polarizing 3D display technology. The RDZ display technology employs cheap polarizing glasses, and the improvement to a display panel is that an additional liquid crystal cell (Pi-Cell) is arranged in front of the display panel, so that high-speed switchover is performed between two polarization directions during displaying, and two eyes of an audience may see different images. In comparison to the shutter 3D display technology and the polarizing 3D display technology, the RDZ display technology mainly has the following advantages: 1) the screen resolution may reach the screen resolution of the shutter 3D display technology; 2) the glasses have cheap price and light weight; and, 3) the picture brightness loss is less than those of the shutter 3D display technology and the polarizing 3D display technology.
In the conventional RDZ technology, a liquid crystal cell is attached onto a display panel. The liquid crystal state of the liquid crystal cell includes a bent state and a vertical state. FIG. 1a is a schematic diagram of a liquid crystal cell at a bent state, and FIG. 1b is a schematic diagram of a liquid crystal cell at a vertical state. As shown in FIG. 1a, the liquid crystal in the liquid crystal cell is at a bent state when no voltage is applied to the liquid crystal cell. In this case, if incident polarized light passes through the liquid crystal cell, the phase is delayed by Pi (π), that is, the polarization direction of the polarized light is rotated by 90 degrees, so that the polarization direction of the polarized light passing through the liquid crystal cell is vertical to the polarization direction of the incident polarized light. As shown in FIG. 1b, the liquid crystal in the liquid crystal cell is at a vertical state when a voltage is applied to the liquid crystal cell. In this case, if incident polarized light passes through the liquid crystal cell, the phase is not delayed, that is, the polarization direction of the polarized light remains unchanged, so that the polarization direction of the polarized light passing through the liquid crystal cell is identical to the polarization direction of the incident polarized light.
FIG. 1c is a schematic diagram of a working principle of an RDZ system in the prior art, and FIG. 1d is another schematic diagram of the working principle of an RDZ system in the prior art. As shown in FIG. 1c and FIG. 1d, the RDZ system includes a display panel 11 and a pair of polarizing glasses. A liquid crystal cell is arranged on the display panel 11, and a +λ/4 slide 14 is arranged on the liquid crystal cell. The pair of polarizing glasses includes a left polarizer 17 and a right polarizer 18. The left polarizer 17 is provided thereon with a −λ/4 slide 15, while the right polarizer 18 is provided thereon with a +λ/4 slide 16. Both the polarization direction of the left polarizer 17 and the polarization direction of the right polarizer 18 are a horizontal direction. Wherein, FIG. 1c shows the working principle of the nth frame of display picture, and FIG. 1d shows the working principle of the (n+1)th frame of display picture. The liquid crystal cell includes a display region 12 and a display region 13. The display region 12 is located above the display region 13. The display region 12 faces an upper half region of the display panel 11, while the display region 13 faces a lower half region of the display panel 11. As shown in FIG. 1c, during displaying the nth frame of display picture, the liquid crystal state of the display region 12 is a vertical state, and the liquid crystal state of the display region 13 is a bent state. The polarization direction of a first display picture displayed by the upper half region of the display panel 11 is a horizontal direction, and the polarization direction is still the horizontal direction after the first display picture transmits through the display region 12 with a vertical state as the liquid crystal state; however, the polarization direction of a second display picture displayed by the lower half region of the display panel 11 is a horizontal direction, but the polarization direction is turned into a vertical direction after the second display picture transmits through the display region 13 with a bent state as the liquid crystal state. The first display picture and the second display picture are turned into circular polarized light in different rotation directions after passing through the +λ/4 slide 14. Subsequently, the first display picture successively passes through the −λ/4 slide 15 and the left polarizer 17 and then is received by the left eye of a user, while the second display picture successively passes through +λ/4 slide 16 and the right polarizer 18 and then is received by the right eye of the user. As shown in FIG. 1d, during displaying the (n+1)th frame of display picture, the liquid crystal state of the display region 12 is a bent state, and the liquid crystal state of the display region 13 is a vertical state. The polarization direction of a second display picture displayed by the upper half region of the display panel 11 is a horizontal direction, and the polarization direction is turned into a vertical direction after the second display picture transmits through the display region 12 with a bent state as the liquid crystal state; however, the polarization direction of a first display picture displayed by the lower half region of the display panel 11 is a horizontal direction, but the polarization direction is still the horizontal direction after the first display picture transmits through the display region 13 with a vertical state as the liquid crystal state. The first display picture and the second display picture are turned into circular polarized light in different rotation directions after passing through the +λ/4 slide 14. Subsequently, the first display picture successively passes through the −λ/4 slide 15 and the left polarizer 17 and then is received by the left eye of a user, while the second display picture successively passes through +λ/4 slide 16 and the right polarizer 18 and then is received by the right eye of the user.
In conclusion, the display panel 11 realizes partition polarization display by a liquid crystal cell. After passing through two display regions of the liquid crystal cell, the polarization direction of a first display picture is vertical to that of a second display picture. The two display regions of the liquid crystal cell are switched between a bent state and a vertical state, thereby realizing a high-speed switchover between two polarization states. As both the driving frequency of the first display picture and that of the second display picture are 120 Hz, in two adjacent frames of display pictures, the left eye receives one complete left-eye parallax picture every 1/60 s, while the right eye receives one complete right-eye parallax picture every 1/60 s.
However, in the prior art, a liquid crystal cell needs to be attached onto a display panel. As the display panel is large in size, the liquid crystal cell needs to have many raw materials, and the technological process of attaching the liquid crystal cell onto the display panel is relatively complicated, so that the production cost is greatly improved.